I don't know of any patents applicable to what I am doing, so I am OK. Right?

Wrong. I don't know where this odd notion that ignorance makes things legally OK comes from, but I have heard it expressed a number of times. It would be deeply paranoid to never do anything in case there is a legal problem. However, patent laws are a constant risk anyone developing things must face. Implementing a standard that is 20 years old, may be relatively safe, though.:-)